Should I understand that you're not actually sure that the engine is 250cc, hence it cannot be used as a search criteria to look for the car ?
There's nothing to stop you using it for your Search as there's a good chance that it is 250cc; on the other hand it might only be 150cc, I'm not sure.
I'm going to be interested in the outcome of this puzzle! I take it you only know that it's a motorcycle engine, and that it could be up to 250cc.. You don't know the make of engine, so you clearly won't know what engine sizes they manufactured. I'm just curious to know why you know the engine is below 250cc but don't know its capacity.
Sorry if this comes across as rude - it's not meant to be! This puzzle's a doozy.